Add parseDotInt

Author: IvanGoncharov

AGENTS.md

@@ -79,6 +79,10 @@ Keep these documents up to date when behaviour changes.
 
 ## Workflow
 
+**Every step in this workflow is mandatory. After completing any task, go through
+the full list and confirm each step has been done before considering the task
+complete. Never skip a step silently — if a step is not applicable, state why.**
+
 1. Before writing any code, search the codebase for similar patterns and match
    their style (see first section).
 2. Verify any assumption about Graphviz output by running the `dot` binary

src/parser.ts

@@ -9,9 +9,6 @@ import {
 import { formatValueForDiagnostics } from './utils.ts';
 import type { Diagnostic, OverrideAttributes } from './viz.ts';
 
-// To make parser internally consistent, all characters are read as UTF-16:
-/* eslint-disable unicorn/prefer-code-point */
-
 const Char = {
   '\t': 0x09,
   '\n': 0x0a,
@@ -163,10 +160,14 @@ class Lexer {
   }
 
   #readChar(): number {
+    // To make parser internally consistent, all characters are read as UTF-16:
+    /* eslint-disable unicorn/prefer-code-point */
     return this.#dotStr.charCodeAt(this.#nextIndex++);
   }
 
   #peekChar(): number {
+    // To make parser internally consistent, all characters are read as UTF-16:
+    /* eslint-disable unicorn/prefer-code-point */
     return this.#dotStr.charCodeAt(this.#nextIndex);
   }
 
@@ -1107,4 +1108,10 @@ class Parser {
   }
 }
 
+export function isNumberToken(str: string): boolean {
+  const lexer = new Lexer(str);
+  const token = lexer.nextToken();
+  return token.kind === Kind.Number && token.length === str.length;
+}
+
 export const parseDot = Parser.parseDot;

src/utils.ts

@@ -1,7 +1,19 @@
+import {
+  NormalizedAttributes,
+  type NormalizedAttributeValue,
+} from './normalize-graph.ts';
+import { isNumberToken } from './parser.ts';
+
 export function formatValueForDiagnostics(value: string) {
   const truncated = value.length > 20 ? value.slice(0, 17) + '...' : value;
   return JSON.stringify(truncated)
     .replaceAll(String.raw`\"`, '"')
     .replaceAll(String.raw`\\`, '\\')
     .slice(1, -1);
 }
+
+export function parseDotNumber(value: NormalizedAttributeValue): number {
+  return NormalizedAttributes.isText(value) && isNumberToken(value.text)
+    ? Number.parseFloat(value.text)
+    : Number.NaN;
+}

src/viz.ts

@@ -6,7 +6,7 @@ import {
   normalizeGraph,
 } from './normalize-graph.ts';
 import { parseDot } from './parser.ts';
-import { formatValueForDiagnostics } from './utils.ts';
+import { formatValueForDiagnostics, parseDotNumber } from './utils.ts';
 
 export interface OverrideAttributes {
   /** Sets the default graph attributes. This corresponds to the {@link https://www.graphviz.org/doc/info/command.html#-G | `-G`} Graphviz command-line option. */
@@ -258,9 +258,7 @@ export class Viz {
     let dotOutputMaxLineLength = MAX_dotOutputMaxLineLength;
     const linelengthValue = graph.graphAttributes.get('linelength');
     if (linelengthValue !== undefined) {
-      const number = NormalizedAttributes.isText(linelengthValue)
-        ? Number(linelengthValue.text)
-        : Number.NaN;
+      const number = parseDotNumber(linelengthValue);
       if (!Number.isInteger(number) || !isMaxLineLength(number)) {
         return failureResult([
           new RenderingBackendError(

test/render.test.ts

@@ -374,7 +374,9 @@ describe('Viz', () => {
       const viz = await VizPackage.instance();
       const result = viz.renderDot(
         'graph { a[image="test.png"]; b[image="test.png"] }',
-        { images: { 'test.png': { width: 300, height: 200 } } },
+        {
+          images: { 'test.png': { width: 300, height: 200 } },
+        },
       );
 
       expectDot(result).toMatchInlineSnapshot(`
@@ -420,15 +422,18 @@ describe('Viz', () => {
     });
 
     describe('returns an error for invalid `linelength` values', () => {
-      it.for(['-1', '59', '129', '1.5', 'abc', '<0>'])('$0', async (value) => {
-        const viz = await VizPackage.instance();
-        const result = viz.renderDot(`graph { linelength=${value} }`);
-
-        expect(result.status).toBe('failure');
-        expect(stringifyDiagnostics(result.diagnostics)).toBe(
-          "RenderingBackendError: linelength must be '0' or an integer in the [60, 128] range",
-        );
-      });
+      it.for(['-1', '59', '129', '60.5', '"0x60"', '"60a"', 'abc', '<0>'])(
+        '$0',
+        async (value) => {
+          const viz = await VizPackage.instance();
+          const result = viz.renderDot(`graph { linelength=${value} }`);
+
+          expect(result.status).toBe('failure');
+          expect(stringifyDiagnostics(result.diagnostics)).toBe(
+            "RenderingBackendError: linelength must be '0' or an integer in the [60, 128] range",
+          );
+        },
+      );
     });
 
     it('accepts URLs for image names', async () => {